The present invention is directed to a process of forming primary amines from olefins, synthesis gas and ammonia.
In the past lower aliphatic amines have generally been prepared by one of four commercial processes. In one process, alcohols are reacted with ammonia in the presence of a dehydrating agent, such as alumina to produce a primary, secondary or tertiary amine depending on the ratio of reactants used. A second commercial method comprised reacting an alcohol with ammonia in the presence of hydrogen and a hydrogenation catalyst, such as nickel. This method normally produced a mixture of amines.
A third method required the reaction of aldehydes with ammonia and hydrogen in the presence of a hydrogenation catalyst such as copper or nickel. Again, the product was a mixture of amines. The commercial method of forming fatty amines was accomplished by reacting a fatty acid or its ester with ammonia to form the nitrile and then hydrogenating the nitrile to form the amine.
The principle of obtaining amines starting from an olefin, hydrogen, CO and ammonia or substituted ammonia is known. See U.S. Pat. Nos. 2,422,631, 2,497,310 and 3,513,200. In these processes the selectivity for amines is only moderate and the selectivity to primary amines is poor.
U.S. Pat. No. 4,096,150 discloses a process for preparation of tertiary amines in high selectivity by reacting an olefin, hydrogen and CO with a secondary amine in the presence of a coordination complex catalyst of a Group VIII metal and a ligand, the donor atom of which is oxygen, nitrogen or sulfur.
Processes for producing secondary and tertiary amines are also taught in the following: U.S. Pat. No. 4,250,115 which uses a rhodium or ruthenium-containing catalyst; J. Org. Chem. 1980, 45, 3370-3372 which discusses the use of a variety of Group VIII transition-metal carbonyl catalyst precursors, including the novel mixed-metal ruthenium/iron; and J. Org. Chem. 1982, 47, 445-447 which discloses a high yield one step process for synthesis of tertiary and secondary amines from olefins, carbon monoxide, water and a nitrogen source using a rhodium-based compound as a catalyst.
U.K. patent application No. GB 2.070010 A discloses a process for producing secondary amines by reacting an olefinic compound, carbon monoxide, ammonia and water in an inert liquid medium in the presence of a catalyst comprising Rh or a Rh salt, carbonyl, oxide or complex.
Aminomethylation of olefins using carbon monoxide and water is disclosed in U.S. Pat. No. 4,292,242 wherein a mixed ruthenium carbonyl, iron carbonyl catalyst is employed.
There seems to be little art on the production of primary amines from synthesis gas, water and ammonia. Large quantities of linear alkyl primary amines are presently produced from the natural fatty acids in coconut oil, palm oil, tallow, etc. The market for these amines exceeds 100 mm lbs/yr. with applications in the rubber and detergent industries as chemical intermediates.
In U.S. Pat. No. 4,299,985, a process is disclosed which is a two-step process for producing linear alkyl primary amines from alpha olefins via oxoamination process comprising the addition of hydrogen and carbon monoxide to olefins in the presence of ligand-stabilized platinum(II) halide catalysts with Group IVB metal halide cocatalysts and reductive amination of said aldehydic intermediates in the presence of oxide supported nickel catalysts.
Japan Kakai Tokkyo Koho No. 81 92,839 to Mitsubishi discloses a process where primary amines were prepared by treating .alpha.-olefins (C.sub.n) with CO, H.sub.2 and NH.sub.3 in an alcohol solvent containing cobalt and a tertiary phosphine. In this procedure the selectivity for C.sub.n+1 primary amines was moderate, about 30%. The production of C.sub.2n+2 primary amines is not reported in this patent.
It would be a considerable advance in the art to produce much desired primary amines from easily obtainable and inexpensive reactants such as synthesis gas and ammonia using catalysts which would be commercially economical. In addition, it would be a considerable advance in the art to obtain selectivities for primary amines which are much improved over other methods used in the art.